Because of the fact that many substances found in an average home are extremely dangerous and often life threatening, particularly if consumed by a child of tender years, much emphasis has been placed on packaging many such substances in containers provided with child-resistant caps. For examples, many drugs, both prescription and over-the-counter, are so packaged, as are some dangerous liquid and particulate substances such as anit-freeze for automobiles, drain cleaners, furniture polishes, etc.
Most of the child-resistant caps which so far have been developed fall into either of two general classes. Some of the caps consist of two separate parts which must be assembled to each other before being placed upon the containers which they are to fit. Others have been so designed as to consist of only one integral or unitary piece, thus reducing the cost of manufacture by eliminating the necessity for a second mold and for an assembly task.
The most successful of the child-resistant closures usually have had two features in common. First, in order to remove or open the closure, it has been necessary that two separate and dissimilar movements or actions take place. It has been found that a child of tender years, say six or less, usually does not readily comprehend how these two dissimilar actions must be performed, although an older child or an adult can do so by reading the instructions which usually are printed or molded on the closures. Secondly, some of the most successful child-resistant closures have also had the property of clearly indicating to an observing adult whether or not the closure is in child-resistant status or merely has been returned to its container without being restored to protective condition.
Unfortunately, many other substances which commonly are found in domestic situations have not yet been provided with satisfactory child-resistant closures. For examples, toilet bowl cleaning liquids, dishwashing liquids, and others, which usually are packaged in containers having dispensing openings, still appear in the market place with closures which an average small child can readily open.
Some closures for such substances have been provided with what might be called "snap-caps," i.e., caps which require that they be removed by the exercise of a fairly substantial amount of force, as, for example, to lift one edge so that the closure can be opened. The cap disclosed in Babiol U.S. Pat. No. 4,010,875 would possess some child-resistant features simply by reason of the fact that a small amount of force is required to disengage the closing lid from the cap body so that it can be swung into open position and the content material dispensed from the container. However, it also has been found that where but a single movement is required, as in the Babiol closure, even a very small child readily can open the closure. In many cases, the child holds the container in one hand and bites into the cap, whereupon he possesses more than adequate strength to open the closure.
Many prior art child-resistant caps can be replaced upon their containers in what seems to be closed position without actually being re-established in child-resistant status. As a result, if the user is inattentive or a little bit careless, it may seem that the closure is safe although it really is not.
It is, therefore, the principal object of the invention to provide a child-resistant dispensing closure particularly designed to be utilized on containers of liquid materials which are dispensed in small quantities.
It is a second and equally important object of the instant invention to provide a child-resistant dispensing closure which positively indicates whether or not it is in protective status and which automatically returns to child-resistant status every time it is closed.
Yet another object of the instant invention is to provide a child-resistant dispensing closure which requires that two completely dissimilar actions be simultaneously performed in order to open the closure.
And yet another object of the instant invention is to provide a child-resistant dispensing closure having the foregoing features which readily can be manufactured as a single, unitary piece of resilient, resinous material such as polypropylene or the like, thus enabling high-speed production in multi-cavity molds in order to minimize cost. A further object of the instant invention is to provide a unitary child-resistant dispensing closure, the parts of which have exteriors so designed that the closures may be placed upon containers by the use of conventional automatic capping machines.